Added comments

Author: chen-robert

src/homecoming/GamePanel.java

@@ -19,6 +19,9 @@
 import javax.swing.JPanel;
 
 public class GamePanel extends JPanel {
+	/*
+	 * This known as a static constructor
+	 */
 	static {
 		BufferedImage img = null;
 		BufferedImage background = null;
@@ -32,24 +35,34 @@ public class GamePanel extends JPanel {
 		backgroundImg = background;
 		heartImg = makeColorTransparent(img, Color.WHITE);
 	}
+
 	static final Image heartImg;
 	static final Image backgroundImg;
 	static final Font font = new Font("Courier", Font.BOLD, 30);
 
 	@Override
 	public void paintComponent(Graphics g) {
+		/*
+		 * The getWidth() and getHeight() methods are inherited from JFrame
+		 */
 		g.setColor(Color.WHITE);
 		g.fillRect(0, 0, getWidth(), getHeight());
 
 		g.drawImage(backgroundImg, 0, 0, getWidth(), getHeight(), null);
 
-
+		/*
+		 * Draw the greeting in the center of the screen
+		 */
 		g.setColor(Color.WHITE);
 		g.setFont(font);
 		drawCenteredString(g, String.format(Main.GREETING, Main.NAME), new Rectangle(0, 0, getWidth(), getHeight()),
 				font);
-		
-		for (Heart heart : Main.state.getHearts()) {
+
+		/*
+		 * Draw all of the hearts. Note that because it is drawn later, these will show
+		 * up on top of the text and background.
+		 */
+		for (Heart heart : Main.gameState.getHearts()) {
 			g.drawImage(heartImg, heart.pos.x, heart.pos.y, GameState.FALLING_HEART_SIZE, GameState.FALLING_HEART_SIZE,
 					null);
 		}
@@ -71,7 +84,8 @@ public void drawCenteredString(Graphics g, String text, Rectangle rect, Font fon
 		g.drawString(text, x, y);
 	}
 
-	// Copied from https://www.javaworld.com/article/2074105/making-white-image-backgrounds-transparent-with-java-2d-groovy.html
+	// Copied from
+	// https://www.javaworld.com/article/2074105/making-white-image-backgrounds-transparent-with-java-2d-groovy.html
 	public static Image makeColorTransparent(final BufferedImage im, final Color color) {
 		final ImageFilter filter = new RGBImageFilter() {
 			// the color we are looking for (white)... Alpha bits are set to opaque

src/homecoming/GameState.java

@@ -16,12 +16,19 @@ public GameState() {
 		hearts = new ArrayList<>();
 	}
 
+	/*
+	 * Update the game state
+	 */
 	public void update() {
 		counter++;
+		
+		/*
+		 * Every 25 ticks, create a new heart
+		 */
 		if(counter % 25 == 0) {			
-			Point pos = new Point((int) (500 * Math.random()), 0);
+			Point position = new Point((int) (500 * Math.random()), 0);
 			int speed = (int) (4 * Math.random()) + 2;
-			hearts.add(new Heart(pos, speed));
+			hearts.add(new Heart(position, speed));
 		}
 
 		for (Heart heart : hearts) {

src/homecoming/Heart.java

@@ -2,10 +2,13 @@
 
 import java.awt.Point;
 
+/*
+ * Wrapper for heart objects. We need to store both position and speed.
+ */
 public class Heart {
 	public final Point pos;
 	public final int speed;
-	
+
 	public Heart(Point p, int speed) {
 		pos = p;
 		this.speed = speed;

src/homecoming/Main.java

@@ -6,9 +6,13 @@
 
 public class Main {
 	static final String NAME = "Alex";
+	
+	/*
+	 * This is a format string, passed to String.format(GREETING, NAME);
+	 */
 	static final String GREETING = "Homecoming %s?";
 
-	static final GameState state = new GameState();
+	static final GameState gameState = new GameState();
 	public static void main(String args[]) throws InterruptedException {
 		JFrame frame = new JFrame("Homecoming?");
 
@@ -26,7 +30,13 @@ public static void main(String args[]) throws InterruptedException {
 		while (true) {
 			long startTime = System.currentTimeMillis();
 
-			state.update();
+			/*
+			 * Update the game state
+			 */
+			gameState.update();
+			/*
+			 * Repaint the frame. 
+			 */
 			frame.repaint();
 
 			long elapsedTime = System.currentTimeMillis() - startTime;